Mercurial > hg > nginx
view src/os/win32/ngx_wsasend_chain.c @ 6133:af7eba90645d
Win32: shared memory base addresses and remapping.
Two mechanisms are implemented to make it possible to store pointers
in shared memory on Windows, in particular on Windows Vista and later
versions with ASLR:
- The ngx_shm_remap() function added to allow remapping of a shared memory
zone to the address originally used for it in the master process. While
important, it doesn't solve the problem by itself as in many cases it's
not possible to use the address because of conflicts with other
allocations.
- We now create mappings at the same address in all processes by starting
mappings at predefined addresses normally unused by newborn processes.
These two mechanisms combined allow to use shared memory on Windows
almost without problems, including reloads.
Based on the patch by Sergey Brester:
http://mailman.nginx.org/pipermail/nginx-devel/2015-April/006836.html
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Mon, 27 Apr 2015 18:25:42 +0300 |
parents | de68ed551bfb |
children | 2cd019520210 |
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/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> #include <ngx_event.h> #define NGX_WSABUFS 8 ngx_chain_t * ngx_wsasend_chain(ngx_connection_t *c, ngx_chain_t *in, off_t limit) { int rc; u_char *prev; u_long size, sent, send, prev_send; ngx_err_t err; ngx_event_t *wev; ngx_array_t vec; ngx_chain_t *cl; LPWSABUF wsabuf; WSABUF wsabufs[NGX_WSABUFS]; wev = c->write; if (!wev->ready) { return in; } /* the maximum limit size is the maximum u_long value - the page size */ if (limit == 0 || limit > (off_t) (NGX_MAX_UINT32_VALUE - ngx_pagesize)) { limit = NGX_MAX_UINT32_VALUE - ngx_pagesize; } send = 0; /* * WSABUFs must be 4-byte aligned otherwise * WSASend() will return undocumented WSAEINVAL error. */ vec.elts = wsabufs; vec.size = sizeof(WSABUF); vec.nalloc = NGX_WSABUFS; vec.pool = c->pool; for ( ;; ) { prev = NULL; wsabuf = NULL; prev_send = send; vec.nelts = 0; /* create the WSABUF and coalesce the neighbouring bufs */ for (cl = in; cl && vec.nelts < ngx_max_wsabufs && send < limit; cl = cl->next) { if (ngx_buf_special(cl->buf)) { continue; } size = cl->buf->last - cl->buf->pos; if (send + size > limit) { size = (u_long) (limit - send); } if (prev == cl->buf->pos) { wsabuf->len += cl->buf->last - cl->buf->pos; } else { wsabuf = ngx_array_push(&vec); if (wsabuf == NULL) { return NGX_CHAIN_ERROR; } wsabuf->buf = (char *) cl->buf->pos; wsabuf->len = cl->buf->last - cl->buf->pos; } prev = cl->buf->last; send += size; } sent = 0; rc = WSASend(c->fd, vec.elts, vec.nelts, &sent, 0, NULL, NULL); if (rc == -1) { err = ngx_errno; if (err == WSAEWOULDBLOCK) { ngx_log_debug0(NGX_LOG_DEBUG_EVENT, c->log, err, "WSASend() not ready"); } else { wev->error = 1; ngx_connection_error(c, err, "WSASend() failed"); return NGX_CHAIN_ERROR; } } ngx_log_debug2(NGX_LOG_DEBUG_EVENT, c->log, 0, "WSASend: fd:%d, s:%ul", c->fd, sent); c->sent += sent; in = ngx_chain_update_sent(in, sent); if (send - prev_send != sent) { wev->ready = 0; return in; } if (send >= limit || in == NULL) { return in; } } } ngx_chain_t * ngx_overlapped_wsasend_chain(ngx_connection_t *c, ngx_chain_t *in, off_t limit) { int rc; u_char *prev; u_long size, send, sent; ngx_err_t err; ngx_event_t *wev; ngx_array_t vec; ngx_chain_t *cl; LPWSAOVERLAPPED ovlp; LPWSABUF wsabuf; WSABUF wsabufs[NGX_WSABUFS]; wev = c->write; if (!wev->ready) { return in; } ngx_log_debug1(NGX_LOG_DEBUG_EVENT, c->log, 0, "wev->complete: %d", wev->complete); if (!wev->complete) { /* post the overlapped WSASend() */ /* the maximum limit size is the maximum u_long value - the page size */ if (limit == 0 || limit > (off_t) (NGX_MAX_UINT32_VALUE - ngx_pagesize)) { limit = NGX_MAX_UINT32_VALUE - ngx_pagesize; } /* * WSABUFs must be 4-byte aligned otherwise * WSASend() will return undocumented WSAEINVAL error. */ vec.elts = wsabufs; vec.nelts = 0; vec.size = sizeof(WSABUF); vec.nalloc = NGX_WSABUFS; vec.pool = c->pool; send = 0; prev = NULL; wsabuf = NULL; /* create the WSABUF and coalesce the neighbouring bufs */ for (cl = in; cl && vec.nelts < ngx_max_wsabufs && send < limit; cl = cl->next) { if (ngx_buf_special(cl->buf)) { continue; } size = cl->buf->last - cl->buf->pos; if (send + size > limit) { size = (u_long) (limit - send); } if (prev == cl->buf->pos) { wsabuf->len += cl->buf->last - cl->buf->pos; } else { wsabuf = ngx_array_push(&vec); if (wsabuf == NULL) { return NGX_CHAIN_ERROR; } wsabuf->buf = (char *) cl->buf->pos; wsabuf->len = cl->buf->last - cl->buf->pos; } prev = cl->buf->last; send += size; } ovlp = (LPWSAOVERLAPPED) &c->write->ovlp; ngx_memzero(ovlp, sizeof(WSAOVERLAPPED)); rc = WSASend(c->fd, vec.elts, vec.nelts, &sent, 0, ovlp, NULL); wev->complete = 0; if (rc == -1) { err = ngx_errno; if (err == WSA_IO_PENDING) { ngx_log_debug0(NGX_LOG_DEBUG_EVENT, c->log, err, "WSASend() posted"); wev->active = 1; return in; } else { wev->error = 1; ngx_connection_error(c, err, "WSASend() failed"); return NGX_CHAIN_ERROR; } } else if (ngx_event_flags & NGX_USE_IOCP_EVENT) { /* * if a socket was bound with I/O completion port then * GetQueuedCompletionStatus() would anyway return its status * despite that WSASend() was already complete */ wev->active = 1; return in; } ngx_log_debug2(NGX_LOG_DEBUG_EVENT, c->log, 0, "WSASend: fd:%d, s:%ul", c->fd, sent); } else { /* the overlapped WSASend() complete */ wev->complete = 0; wev->active = 0; if (ngx_event_flags & NGX_USE_IOCP_EVENT) { if (wev->ovlp.error) { ngx_connection_error(c, wev->ovlp.error, "WSASend() failed"); return NGX_CHAIN_ERROR; } sent = wev->available; } else { if (WSAGetOverlappedResult(c->fd, (LPWSAOVERLAPPED) &wev->ovlp, &sent, 0, NULL) == 0) { ngx_connection_error(c, ngx_socket_errno, "WSASend() or WSAGetOverlappedResult() failed"); return NGX_CHAIN_ERROR; } } } ngx_log_debug2(NGX_LOG_DEBUG_EVENT, c->log, 0, "WSASend ovlp: fd:%d, s:%ul", c->fd, sent); c->sent += sent; in = ngx_chain_update_sent(in, sent); if (in) { wev->ready = 0; } else { wev->ready = 1; } return in; }